1. Field of the Invention
The present invention relates to a head assembly attaching method using ball caulking and to a cylindrical jig and caulking ball used for the method.
2. Description of Related Art
A head assembly attaching method by ball caulking is disclosed in, for example, Japanese Unexamined Patent Application Publications No. H07-85635 and No. H05-303855.
FIG. 7 is a partly broken side view illustrating an example of a head assembly attaching method according to a related art. In FIG. 7, a carriage 101 has a plurality of arms 103 each having a through hole 105 to which a head assembly 109 is fitted by caulking with the use of a steel caulking ball 107.
The head assembly 109 includes a head suspension 111 and a flexure (not illustrated) attached to the head suspension 111. The flexure has a slider 113.
The head suspension 111 includes a load beam 121 having a resilient part 115 and a rigid part 116. The head suspension 111 also includes a base part 118 that is integrated with the resilient part 115. To the base part 118, a base plate 117 is attached. The slider 113 is arranged at a front end of the load beam 121 to form a head. The slider 113 is attached to the flexure, and the flexure is supported with the load beam 121.
The base plate 117 has a boss 117a and a flange 117b. The boss 117a is inserted into the through hole 105 of the arm 103. A plurality of the head assemblies 109 are arranged for the arms 103 of the carriage 101, respectively, and the caulking ball 107 is successively passed through the bosses 117a of the base plates 117, to expand and plastically deform the bosses 117a in the through holes 105, thereby fixing the base plates 117 of the head assemblies 109 to the holes 105 of the arms 103.
If the flange 117b of the base plate 117 is deformed at the time of caulking, the load and resonance characteristics of the head assembly 109 will deteriorate. The flange 117b, therefore, must not be deformed, or the head assembly 109 will not satisfy requirements for high accuracy.
In this regard, Japanese Unexamined Patent Application Publication No. H07-192420 ('420 document) proposes a base plate having a special shape so that a flange of the base plate will not be deformed by caulking and Japanese Unexamined Patent Application Publication No. 2007-213640 ('640 document) proposes a technique of applying ultrasonic vibration several times during caulking.
The base plate of '420 document has a problem of increasing costs due to the special shape of the base plate.
The ultrasonic vibration technique of '640 document has a problem of increasing costs because applying ultrasonic vibration several times increases the number of processes.